If you are developing a theme from scratch you’ll have to consider what value you want to give to the <title> tag in each page. The <title> tag is crucially important for SEO purposes and most likely users will use a plugin such as WordPress SEO Plugin or others to overwrite this, but still you need to set it to something to start with and if you care just a bit you’ll consider making them dynamic based on each page as oposed to hard-coding a fixed sentence.

It doesn’t have much more to it than playing around with the page title, the blog title and blog tagline and giving them some kind of order and divisions… You can most definitely write your own code for this, but here is an already built snippet that is a great starting point.

Tip 1: For those of you who are really lost here… this snippet goes in your header.php file, between the opening   and the closing